Articulator



y 17, 1956 F. M. CORDELL 2,754,588

ARTICULATOR Filed Dec; 9, 1952 4 Sheets-Sheet 1 11\ VENTOR Van. UT): KS

July 17, 1956 F. M. CORDELL 2,754,588

ARTICULATOR Filed Dec. 9, 1952 4 Sheets-Sheet 2 INVENTOR aim/1M,

ATTORNEY July 17, 1956 F. M. CORDELL 2,754,588

ARTICULATOR Filed Dec. 9, 1952 4 Sheets-Sheet 3 INVENTOR J1 fouls,

Km... LL) Loc.\

ATTORNEY July 17, 1956 F. M. CORDELL 2,754,538

ARTICULATOR Filed Dec. 9, 1952 4 Sheets-Sheet 4 INVENTOR ATTORNEY UnitedStates Patent Ofi ce Patented July 17, 1956 ARTICULATOR Finton M.Cordell, Baltimore, Md., assignor to Harry B. Schwartz, Inc., Baltimore,Md., a corporation of Mary land Application December 9, 1952, Serial No.324,999

22 Claims. (Cl. 32-32) The present invention relates to a method and theapparatus employed in the construction of artificial dentures. Moreparticularly, the present invention relates to the method and apparatusemployed in constructing artificial dentures whereby an exact fitting ofthe finished dentures is obtained.

It is now generally recognized that oral discomfort resulting frominadequate dental prosthesis is injurious to the nervous system and canresult in general organic malfunction. It is extremely important,therefore, that considerable time and effort be expended and the bestavailable equipment be utilized in the construction of dentures for anindividual case, particularly since it is possible that inadequate orill fitting dentures can result in the physical breakdown of anindividual.

The science and art of dental prosthesis have been developed to a degreewhereby adequate artificial dentures are provided for those individualswho have unfortunately lost their natural dentition. With the aid ofartificial dentures, these latter individuals have been able to continuein their ordinary course of life without undue tooth consciousness.However, the science and art of dental prosthesis, although havingdeveloped techniques to construct artificial dentures which areadequate, have not, prior to the instant invention, discovered a processwhereby artificial dentures can be constructed and then fitted in thepatients mouth without various adjustments having to be made to conformthe dentures to the particular characteristics of the patients mouth.

It has become the general procedure in the field of dental prostheticsto utilize a mechanical device or articulator to aid in the constructionof the artificial dentures. Articulators are constructed with the viewthat if the patients jaw or mandible movements can be translated to amechanical movement, the complete denture can be formed thereon inconformance with the patients natural jaw movements. Unfortunately, themandible as it moves forward in protrnsive position and to the sidelaterally does not open and close purely as a hinge, but in opening andclosing also moves forward and backward due to the inclined plane of thebony fossa combined with the action of the meniscus and muscularattachments. Moreover, the angle of inclination of the inclined plane,or condylar indication, will vary for some individuals with each side ofthe head. These variations, if not compensated for in the completeddentures, will often result in improper maxillomandibular relation ordisharmony of the teeth in function.

Prior to the instant invention, the heretofore known methods which haveemployed articulators have not succeeded in solving the problem ofaccurately transferring the natural movements of the patients jaw to thearticulator. Even though the heretofore known articulators can beadjusted to simulate some of the human mandible movements, denturesconstructed on these articulators do not have correct occlusioninitially and have to be custom-fitted in the patients month. More thanoften additional grinding and fittings are necessary before the denturesproperly fit the patients mouth, and even then post fittings andadjustments are frequently required. Not only are the heretofore knowndenture techniques using articulators not capable of producing correctlyfitting dentures in the first instance, but they are of little value forthose edentulous patients who have different angles of inclination orvariations in the condylar indications on either side of the head. Forthese individuals who have heretofore been considered dental cripples,there is no means or method heretofore known by which correctly fittingdentures can be constructed without considerable difficulty.

It is therefore an object of the present invention to provide a methodof constructing artificial dentures whereby the finished dentures willcorrectly fit the patients mouth.

Another object of the present invention is to provide a method ofutilizing articulating apparatus that will correctly transfer the humanmandible movements onto an articulator.

Still another object of the present invention is to provide a method ofutilizing articulating apparatus that results in the exact reproductionof the desired movements of the human mandible.

Still another object of the present invention is to provide anadjustment plate by which the mandible cast is adjusted in accordancewith the patients mandibular movements.

Other objects and the nature and advantages of the instant inventionwill be apparent from the following description taken in conjunctionwith the accompanying drawings, wherein:

Fig. 1 is a side elevational view of an articulator with the maxillarybracket hinged out of position and illustrating the position in whichthe mandibular cast is positioned in the articulator;

Fig. 2 is a side elevational view of the articulator illustrated in Fig.1 showing a primary bite being utilized to correctly position themandibular and maxillary cast in the articulator;

Fig. 3 is a partial view in side elevation of the articulatorillustrating an element for recording a Gothic arch positioned on themandibular cast;

Fig. 4 is a vertical sectional view of an element for tracing a Gothicarch positioned on the maxillary cast;

Fig. 5 is a plan view of the articulator with the maxillary cast hingedout of position and the recording element positioned on the mandibularcast prior to adjustment of the mandibular cast adjustment plate;

Fig. 6 is a plan view of the articulator similar to Fig. 6 afteradjustment of the mandibular cast by means of the mandibular castadjustment plate;

Fig. 7 is a plan view of the articulator, illustrating locking means forlocking the mandibular cast in centric relation, the tracing andrecording elements shown in Figs. 3 and 4 positioned in the articulatorprior to the final mounting of the maxillary cast;

Fig. 8 is a plan view of the articulator illustrating a locking meansfor locking the maxillary and mandibular casts in protrnsive position,the maxillary cast being shown in canted position;

Fig. 9 is an exploded view in perspective of the adjustable mandibularmounting plate upon which the mandibular cast is mounted; and

Fig. 10 is a view taken along the line 10-10 of Fig. 2.

It is a generally accepted fact that if the articulator employed in theconstruction of artificial dentures is able to exactly duplicate themovements of the patients lower jaw or mandible, the dentures will beconstructed in conformity with the patients oral characteristics. One ofthe techniques employed in attempting to reproduce the movement of thelower jaw utilizes a Gothic arch tracing device. The Gothic arch tracingdevice records the movements of the patients lower jaw in the form of anarch. If the arch recorded on the tracing device is exactly duplicatedby the articulator, the dentures constructed on that articulator will bein conformance with the movements of the lower jaw of the patient andwill thereby be in proper occlusion when placed in the patients mouth.The present invention is designed to position the maxillary andmandibular casts, which duplicate the patients upper and lower gumimpressions, in such a manner that the Gothic arch recorded by thepatient will be exactly duplicated. The dentures thus formed on thearticulator described in the present invention will, when inserted inthe patients mouth, be in proper occlusion and any additionaladjustments or grinding of the dentures is thereby obviated.

Referring to Figs. 1 and 2 of the drawings, the articulator embodies inthe present invention is illustrated therein generally at and includes abase 12. integrally formed on the underside of the base 12 and locatedat the corners thereof are feet 14. Positioned at the rear corners ofthe base 12 are vertical or condylar posts 16 which extend upwardly,terminating in circular or condylar heads 18. The condylar heads 18 areadapted to simulate the position of the human condyles and are providedwith adjustments to compensate for condylar inclination deviations aswill hereinafter be described. Each of the conylar posts 16 is rotatablypositioned in the base 12 and is engaged by a stud 20 which secures theposts 16 in any desired adjusted position.

Mounted for rotation in each of the condylar heads 18 is a rotatableelement 22 which has a slot 24 formed therein. Each of the rotatableelements 22 is adjusted in a condylar head 18 by means of a lock nut 26.Each of the lock nuts 26 threadedly engages a screw stud 28 whichextends through a slot 29 formed in the upper portion of the condylarheads 18 and which is secured to the rotatable element 22. It isapparent that the lock nut 26 locks the rotatable element 22 in anydesired position which, in effect, adjusts the position of the slot 24with respect to the horizontal. Positioned in each of the slots 24 is acondylar ball 30 which is adapted to be movable lengthwise in the slot24 but is prevented from moving laterally therein. A suitable lockingdevice 32 is secured to the rotatable element 22 and firmly locks thecondylar ball 30 in the slot 24. Each of the balls 30 is secured to anend of a shaft 35 which defines the hinge axis of a maxillary bracket 38formed integral with the shaft 35 and located perpendicular thereto.Referring to Fig. 2, the maxillary bracket 38 is shown including amounting plate 40 which is attached to the bracket 38 by a mounting nut42. Secured to the front portion of the bracket 33 and dependingdownwardly therefrom is an incisal pin 3-4 which forms the front guideor stop for the bracket 38 as it is hingedly moved on the condylar balls30 secured to the ends of the shaft 35. Secured to the base 12 is alower mounting plate generally indicated at 59, which is adapted to havemounted thereon a cast of the patients lower jaw or mandible. The plateis adjustable, as will hereinafter be described, and cooperates with theupper mounting plate 40 to secure the upper and lower casts of thepatient in the correct mounting position in the articulator.

It is apparent that in the articulator described hereinabove, the basicelements of the human jaw are reproduced therein. If an impression orcast of the patients jaws is made and fixed to the lower mounting plate5% and the uppermounting plate 49, the upper bracket 33 of thearticulator may be hinged upwardly and downwardly along the hinge axisextending through the condylar balls 30 and thereby simulate the openingand closing of the patients jaws. However, it is obvious that the exactmovement of the patients jaws may not be reproduced on the articulatorwithout making additional adjustments to compensate for the specialcharacteristics of the patients jaws in movement. It is a known factthat there are certain characteristics that are common to all patientsand, therefore, if these known facts are applied, the individual casemay be solved with relative simplicity.

It is an accepted anatomical fact that the high points of the naturallower anterior teeth, as they theoretically appear in the patientsmouth, lie in a horizontal plane that includes the high points of thenatural lower posterior teeth, assuming that there has been no wear orabrasion of the teeth. Therefore, theoretically, if an individual ispositioned upright, and if there are no interfering teeth, a planeextending from the high points of the natural lower anterior teeth tothe high points of the natural lower posterior teeth will be horizontal.It follows that if a model or cast of the patients lower jaw ormandible,

in riding the natural anterior and posterior teeth, is reproduced andplaced in an articulator and positioned such that the high points of thenatural lower anterior teeth and the high points of the natural lowerposterior teeth are located in a horizontal plane, then the mandibularcast will be located in a substantially correct vertical position in thearticulator. The positioning of the mandibular or lower cast in thearticulator in the true horizontal position will be described in detailhereinafter. However, for the purpose of initially locating the lowercast horizontally in the articulator, the average distance from thenatural lower anterior teeth in the head to a line extending through thecondyles or intercondylar axis is utilized. The average length of thenatural lower anterior teeth, the average length of the natural lowerposterior teeth, and the average distance of these teeth from thecondylar axis can be determined from known anatomical reference pointsand can be accurately indicated on an edentulous lower model or cast.There fore, if a model or cast of a patients edentulous jaw or mandibleis reproduced and placed in an articulator and positioned such thatcalibrated reference positions, which correspond to the high points ofthe natural lower anterior teeth and the natural lower posterior teeth,lie in a horizontal plane at the average distance from the condylar axisof the articulator, then the mandibular cast indicated at 52 in Fig. 1will be located in a substantially correct vertical position in thearticulator. In order to obtain the correct vertical position of themandibular cast 52, whereby the high points of the natural lower andanterior teeth will lie in a horizontal plane, any convenient means ormethod, such as an ordinary spirit or bubble level can be employed. Thelocation of the edentulous mandibular cast in the proper vertical planeon the articulator will hereinafter be referred to as the correctanatomical average vertical and horizontal position. Once the correctanatomical average vertical and horizontal position of the mandibularcast is obtained, plaster is injected beneath the cast, thereby sealingit to the lower mounting plate 50.

Although the lower cast 52 is fixed in the anatomical average verticaland horizontal position in the articulator, it is necessary to obtainthe centric relation of the upper and lower jaws which can then betransferred to the articulator to produce the true horizontal locationof the lower east 52. With the lower cast 52 correctly positioned incentric relation in the articulator, an upper cast indicated at 54 inFig. 2 can then be correctly mounted in the articulator. Centricrelation is defined as the most retruded unstrained position of thecondylar heads in the glenoid fossae at a given degree of opening and isobtained in the present invention by utilizing a Gothic arch tracer. TheGothic arch tracer includes a tracing device that is placed in thepatients mouth, the tracing device being adapted to have the lateral andprotrusive movements of the patients lower jaw recorded thereon. Inrecording the movements of the patients jaw, an arch is tracedthat isproduced by one condylar head moving laterally, the other condylar headacting as a universal pivot. The tracing :ofthis movement produces .aline arses-es starting from a point which is the most retruded positionof the moving condylar head. Moving the opposite condylar head laterallytraces a line that begins from the most retruded position of the movingcondylar head and which cuts across the tracing of the first line at anangle. The lines thus traced are recorded on the tracing device in theform of an arch, the apex of which defines centric relation.

Since the tracing device is actually placed in the patients mouth, it isconstructed from the impression formed on the lower cast 52 and on theupper cast 54 which is a model of the patients upper jaw. However,before the tracing device can be constructed, the upper and lower castsmust be positioned relative to the position of the patients' upper andlower jaws. Referring again to Fig. 2, the upper cast 54 is shownmounted in the articulator on the upper mounting plate 40 and engaging aprimary bite plate 56. The primary bite plate 56 is formed from animpression of the patients upper and lower jaws and when placed in thearticulator between the upper cast 54 and the lower cast 52 will causethe upper and lower casts to approximate the natural position of thepatients upper and lower jaws. The upper cast 54 is then preliminarilysecured to the upper mounting plate 40 by suitable means, such asquicksetting plaster, and the primary bite plate 56 is removed from thearticulator. It is apparent that the upper and lower casts are nowmounted in the articulator in such a manner so as to approximate theanatomical position of the patients upper and lower jaws.

The tracing or recording device utilized in recording the patients jawmovements may be of any conventional type. However, an intraoral type isillustrated and is formed in individual elements comprising a lowerrecording element 66 (Fig. 3) and an upper tracing element 62 (Fig. 4).The lower recording element 60 is constructed by using the lower cast 52as a model and shaping the body of the element 60 in accordance with theimpression formed thereon. The upper tracing element 62 is similarlyformed by using the upper cast as a model and shaping the body of theupper element in accordance with the impression of the upper cast 54.The lower recording element 60 is formed such that when positioned onthe lower cast 52, the upper surface thereof lies in a horizontal plane.Securely fixed to the upper surface of the recording element 60 is arecording plate 64 which forms the surface upon which the Gothic archproduced by the movements of the patients jaws is recorded. Therecording plate 64, when located in the lower cast, lies in a horizontalplane that corresponds to the plane extending through the high points ofthe natural anterior and posterior teeth as these teeth theoreticallyappear in the patients mouth. The recording plate 64 is thereby locatedin the correct anatomical average vertical and horizontal position. Aplate 66 is secured to the lowermost surface of the tracing element 62and a tracing pin 68 is secured thereto. The tracing pin 68 is locatedat approximately the mid point of the upper tracing element 62 and isadapted to contact the recording plate 64 at approximately the mid pointthereof when the tracing device is mounted in the articulator or placedin the patients mouth.

It is apparent that when the tracing device is placed in the patientsmouth, lateral movements of the patients jaws will produce a recordingin the form of an arch on the plate 64, as traced by the tracing pin 68.Protrusive movement of the patients jaw will produce a straight linethat, theoretically, if extended, would extend from the center of thehorizontal projection of the hinge axis of the articulator through theapex of the Gothic arch. In order to obtain a permanent record of thecentric relation recorded by the tracing device, a plaster lock isformed around the upper tracing element 62 and the lower recordingelement 60 with the tracing pin 68 resting on the apex of the Gothicarch. For convenience,

this lock is referred to as the C or centric loclr. Sim ilarly, with thepatients jaws in the most protrusive position, a plaster impression istaken between the upper and lower jaws and forms a permanent record ofthe protrusive position of the patients jaws. The protrusive bite orlock is referred to as the P lock and will be more completely describedhereinafter.

When the lower cast 60 was initially mounted on the lower mounting plate54 of the articulator it was mounted in accordance with averagemeasurements for the average person. However, the jaw measurements ofindividuals vary. That is to say, the condylar width of all persons willnot always be the same and similarly, the distance from theintercondylar axis to the high point of the lower anterior teeth willvary from person to person. It follows, therefore, that a person with awide condylar width will trace a Gothic arch that has an apex that isrelatively a greater distance from the center of the horizontalprojection of a line drawn through the condylar balls 30 or hingle axisof the articulator than a patient having a narrow condylar width.Referring now to Figs. 5 and 6, the lower recording element 60 of theGothic arch tracing device is illustrated positioned in the articulatorwith the Gothic arch recorded thereon. The line a of the Gothic archrepresents the movement of the lower condylar ball 30, as seen in Fig.5, whereas the line b represents the movement of the upper condylar ball30. The lines a and b intersect at the point 0 which is the apex of theGothic arch. A substantially straight line d is formed on the tracingplate 64 by the forward movement of the patients lower jaw andrepresents the protrusive tracing thereof. As discussed above, a Gothicarch tracing represents the extreme lateral and the centric positionfrom which all movements of the lower jaw are made. If the articulatorreproduces this Gothic arch tracing with the tracing device disposed onthe upper and lower casts, then it may be assumed that the movements ofthe patients lower jaw are duplicated by the articulator. However, inorder for the tracing point 68 of the upper tracing element 54 toreproduce the lines a and b in the articulator, it is necessary to firstreposition the lower east 52 in the articulator in accordance with theactual measurement of the angle of the Gothic arch. Since the angle ofthe Gothic arch tracing anatomically is related to the distance betweenthe apex of the arch and the intercondylar axis and the horizontalprojection of a line drawn through the hinge axis of the articulator,this distance can be obtained by utilizing a chart, the data for whichhas been compiled from actual case histories. Thus, by compiling datafrom a series of cases, the relation between the measurement of theangle of the Gothic arch traced by an individual and the distance fromthe apex of the arch to the midpoint of the horizontal projection of thehinge axis will be determined. Consequently, by referring to the chart,the distance for an individual case can be readily determined if theangle of the arch that is traced is measured. It is apparent then thatthe distance obtained will be the distance that the apex of the Gothicarch traced by the patient must be positioned from the midpoint of thehorizontal projection of the line drawn through the hinge axis of thearticulator in order to compensate for the deviations from the averagecondylar width.

An example of a chart is indicated below, the distance from the apex ofthe arch that is traced to the midpoint of the horizontal projection ofthe hinge axis of the articulator being indicated in millimeters:

Angle in degrees: Distance in millimeters By utilizing the protrusiveline d formed by the patient on the tracing plate 64, the lateralposition of the lower cast 60 can also be obtained. The example of theGothic arch tracing illustrated in Fig. 5 shows the protrusive line ddeviated from a line extending from the apex c of the Gothic arch to themidpoint of the line drawn through the hinge axis of the articulator. Bylaterally moving the lower cast 60 until the line d coincides with theline drawn through the apex c of the Gothic arch to the midpointof thehorizontal projection of the articulator hinge axis, the lower cast ispositioned in the same relationship to the line drawn through thearticulator hinge axis that the lower jaw is to the intercondylar ax Inorder to effect the necessary lateral adjustments of the lower east 60,the mounting plate 59 illustrated in Fig. 9 is employed. The mountingplate 50 comprises a movable upper plate 7t) which is generallyrectangular in configuration and which is formed with rounded corners. Aslotted plate 72 normally employed in articu lators is secured in anappropriate recess 7% formed in the upper plate 70 by means of setscrews 76 which extend through the ends of the upper plate 79 and intothe recess 74. Downwardly extending elongated screws 78 are secured inthe upper plate 70 and are formed flush with the upper surface thereof.A fixed lower plate it is adapted to engage the upper plate 70 and has agenerally rectangular configuration with rounded corners similar toplate 70. Large openings 82 are formed in the plate 80 and are adaptedto receive the elongated screws 78 therein. A threaded opening 84 isformed in the center of the lower plate 80 and receives a mounting screw86 which extends through the base 12 of the articulator, thereby fixedlysecuring the plate 89 to the articulator. Adjustment nuts 88 formed witheccentric openings in the body thereof are positioned in the openings 32of the lower plate 80, as seen in Fig. 1G, and are adapted to receivethe elongated screws 73. Lock nuts 9%) are formed with threaded openingsin the body thereof and are adapted to threadedly engage the screws 78for locking the movable plate 70 to the fixed plate it As shown in Fig.10, the locknuts 90, when tightened, force the shoulder of theadjustment nuts 83 against the plate 80 and the uppermost end thereofagainst the plate 7%, thereby firmly securing the upper plate 76 to thefixed lower plate 80. In laterally adjusting the lower east 52 to movethe protrusive line d of the Gothic arch tracing so that it conforms tothe line extending from the apex of the Gothic arch to the center of thehorizontal pro jection of the hinge'axis of the articulator, it is onlynecessary to loosen thelock nuts 96 and rotate the nuts 88. Since thebody of the adjustment nuts has eccentrically located openings formedtherein, rotation of the nuts 83 will cause the movable plate 7% to movelaterally with respect to the fixed plate 89. The adjustable mountingplate 50 thereby provides a simple method of laterally repositioningthelower cast 52 as requiret by the Gothic arch tracing.

Referring now to Fig. 6, the lower east 52 is shown after it has beenlaterally repositioned in accordance with the reading of the chartdiscussed hercinabove. The lower cast 52 has been adjusted laterally bythe lower mounting plate 50 so that the protrusive line (2 lies a lineextending from the apex c of the Gothic arch to the center of thehorizontal projection of the hinge axis of the articulator. With thelower east 52 mounted in the correct horizontal position in thearticulator, the upper and lower elements of'the Gothic arch tracingdevice are locked together with-the C" lock as shown in Fig. 7 andplaced on the lower east 52. The upper east 54 is then mountedpermanently to the upper mounting plate 4'9, utilizing the upper element62 of the Gothic arch tracing device as a guide. It is apparent that theupper and lower casts will then be mounted in centric relation in thearticulator. Since the Gothic arch tracing represents the extremelateral and centric position from which all movements of the lower jaware made, it should follow that .if .a tracing is-made by.moving thearticulator to the right and then to the left laterally, the tracingrecorded by the articulator should identically duplicate the tracingmade by the patient. However, in some instances, due to variations inthe condylar inclinations of the patients head, this tracing will not beduplicated and, therefore, further adjustments in the articulator arenecessary.

The inclined plane or the condylar inclination of the average personmeasures approximately 22 on both sides of the head. However, manyindividuals have different condylar inclinations on either side of thehead and it is for these individuals that the condylar slots 24 must beadjusted in the articulator to compensate for any deviations in thecondylar inclinations. The deviations in the condylar inclinations ofthe patient are recorded by havthe patient move the lower jaw in aprotrusive position and then filling up the space between the upper andlower casts with plaster to form the P or protrusive bite or lock (seeFig. 8). The P lock actually records the space between the upper andlower jaws with relationship to the condyles when the jaws are moved inthe protrusive position and will determine the amount of adjustment ofthe condylar slots 24 that is necessary to reproduce the tracing on theGothic arch tracing device. The protrusive adjustment of the articulatoris obtained after the upper and lower casts have been mounted on thearticulator in centric relationship. The lock nuts 26 for the rotatingelement 22 are loosened and the upper and lower elements of the Gothicarch tracer are placed on the upper and lower casts and the protrusivelock P" is accurately fitted on the lower element of the Gothic archtracing device. Pressure is exerted on the upper bracket 38 and at thesame time one of the rotating elements 22, which includes the condylarslots 24, is loosened and moved back and forth until the upper elementof the Gothic arch tracer firmly and precisely fits protrusive lock P.The process is repeated with the other rotating element 22 and condylarslot 24 until an overall precise and secure seat of the upper tracingclement attached to the upper cast is achieved. The rotating elements 22are then locked in the position thus obtained. Referring to Fig. 8, thecondylar slots have been so adjusted that the shaft 35 has been slightlycanted as seen in the plan view.

In some instances, when the loss of teeth has been irregular over aperiod of years, the lower jaw or mandible usually has been shunted intoa protrusive and lateral position which varies considerably from normal.In these cases, correction for the proper condylar inclination of thecondyles will not always result in an exact reproduction of the Gothicarch tracing by the articulator. Therefore, it is necessary to loosenthe screws 29 located along the rear side of the articulator and then torotate each condylar post 16. The condylar posts 16 are rotated as theupper cast 54 is moved laterally to the left and right over the lowercast 52. The proper position of the condylar posts 16 will beascertained when the articulator is caused to exactly duplicate thetracing traced by the patient. The rotation of the condylar posts 16thus enables the articulator to exactly duplicate the patients tracingrecorded on the Gothic arch tracing device. As shown in Fig. 8, thelower post has been retated to the position shown in dotted lines. Oncethe Gothic arch tracing is duplicated by the articulator, the teeth canbe set up and waxed, invested and processed in the conventional manner.The completed dentures, when placed back on the articulator, arefinished and polished and then removed for insertion into the patientsmouth. Since the method described above enables the articulator toexactly duplicate the Gothic arch tracing scribed by the patient,occlusal adjustments or grinding of the dentures are unnecessary, thedentures exactly fitting the patients mouth when initially insertedtherein.

it is apparentthatthe methodof constructing artificial dentures setforth above will produce dentures that will correctly fit the patient inthe first instance and the necessity for additional grinding oradjusting or post fitting is thereby completely obviated. Actualclinical results have proved that the method and apparatus describedhereinabove produce dentures that fit the patient with proper occlusionand even those patients who have been edentulous for long periods oftime have been accurately fitted with little dilficulty. Moreover, thedilficulty in constructing dentures for those patients who are partiallyor completely edentulous and who have different angles of inclination orvariations in the condylar indications on both sides of the head hasbeen overcome by the application of the method taught by the presentinvention. Since clinical results and analysis have proved that themethod of constructing artificial dentures taught by the presentinvention does produce correctly fitting dentures which do not requirefurther adjustment, it is apparent that the present invention presents areal solution to a very difiicult problem that has existed for manyyears.

It will be obvious to those skilled in the art that various changes maybe made without departing from the spirit of the invention and,therefore, the invention is not limited to what is shown in the drawingsand described in the specification, but only as indicated in theappended claims.

What is claimed is:

1. In a method of construction artificial dentures comprising the stepsof mounting a lower east in an articulator in the correct anatomicalaverage vertical and horizontal position, constructing a Gothic archtracing device to record the patients mandibular movements, mounting thelower element of said tracing device on said lower cast so that theupper surface thereof lies in a horizontal plane, placing said Gothicarch tracing device in the patients mouth and recording the mandibularmovements thereof in the form of a Gothic arch, measuring the angleformed by said Gothic'arch, adjusting the position of said lower cast incentric relation in accordance with the reading of said angle, mountingan upper cast in said articulator in a position determined by theadjusted position of said lower cast, moving said upper cast inprotrusive position, adjusting the condylar heads and posts of saidarticulator so that the Gothic arch traced by the mandibular movementsof the patient will be reproduced when said upper cast is moved relativeto said lower east in said articulator, and mounting teeth in saidcasts, said teeth being arranged to properly occlude due to the properalignment of said upper and lower casts.

2. In a method of constructing artificial dentures, comprising the stepsof forming the maxillary and mandibular casts of the patient, mountingsaid mandibular cast on an articulator so that a horizontal planeextends through reference points corresponding to the high points of thenatural lower anterior and posterior teeth, thereby simulating thelocation of the mandible as it appears in the patients mouth,constructing a tracing device in accordance with the formation of themaxillary and mandibular casts, recording the lateral and protrusivemandibular movements of the patient on said tracing device, measuringthe angle formed by said recording, adjusting the position of saidmandibular cast in accordance with the reading of said angle, mountingsaid maxillary cast in said articulator in a position determined by theadjusted position of said mandibular cast, moving the upper cast in themost protrusive position, adjusting the condylar heads and posts of saidarticulator so that the arch traced by the mandibular movements of thepatient will be reproduced when said maxillary cast is moved relative tosaid mandibular cast, and mounting teeth in said casts, said teeth beingarranged to properly occlude due to the proper alignment of saidmaxillary and mandibular casts.

3. In a method of constructing artificial dentures comprising mounting alower east of the patients mandible in an articulator in the correctanatomical average vertical and horizontal position, recording themovements of said mandible on a tracing device, adjusting the positionof said lower cast in said articulator in accordance with the record ofthe patients mandibular movements, mounting an upper cast of thepatients maxillary in said articulator in centric relation with saidlower cast, moving said upper cast in the protrusive position and thenadjusting the condylar reading of said articulator so that saidarticulator will reproduce the maxillomandibular movements of thepatient, and mounting teeth in said casts, said teeth being arranged toproperly occlude due to the correct positioning of said upper and lowercasts.

4. In a method of constructing artificial dentures comprising the stepsof mounting a lower cast in an articulator in the correct anatomicalaverage vertical and horizontal position, adjusting said lower cast insaid articulator in centric relation in accordance with a record of thepatients mandibular movements, mounting an upper cast in saidarticulator in proper relation to said lower cast, and mounting teeth insaid upper and lower casts, said teeth being arranged to properlyocclude due to the correct positioning of said upper and lower casts.

5. In a method of constructing artificial dentures comprising the stepsof mounting a lower east in an articulator in the correct anatomicalaverage vertical and horizontal position, recording the lateral andprotrusive mandibular movements of the patient in the form of a Gothicarch, measuring the angle of said Gothic arch, adjusting the position ofsaid lower cast in accordance with the measurement of said angle,mounting an upper cast in said articulator to conform to the position ofsaid lower east, moving said upper cast in the most protrusive positionand then adjusting the condylar reading of said articulator so that theGothic arch traced by the manibular movements of the patient will bereproduced when said upper cast is moved relative to said lower cast,and mounting teeth in said casts, said teeth being arranged to properlyocclude due to the correct alignment of said upper and lower casts.

6. In a method of constructing artificial dentures comprising the stepsof forming an upper and lower cast of a patients jaws in the correctanatomical average vertical and horizontal position, constructingrecording means for recording the movements of the patients lower jaw,recording the movements of the patients lower jaw on said recordingmeans, adjusting said lower east in said articulator in accordance withthe recorded reading, mounting an upper cast of the patients upper jawin said articulator in a position determined by the adjusted position ofsaid lower cast, moving the casts in the most protrusive position, andadjusting articulating means thereby causing said articulator toreproduce the patients recording.

7. In a method of constructing artificial dentures comprising the stepsof constructing an upper and a lower cast of a patients jaws, mountingsaid lower east in an articulator utilizing leveling means, saidleveling means locating said lower cast in said articulator in thecorrect anatomical average vertical and horizontal position, adjustingsaid lower cast in said articulator in accordance with the recordedmovements of the patients jaws, mounting said upper cast in saidarticulator in centric relation with said lower cast, moving said uppercast in protrusive position, and adjusting articulating means therebycausing said articulator to reproduce the patients recorded movements.

8. In a method of constructing artificial dentures comprising the stepsof mounting a lower cast of the patients mandible in an articulator inthe correct anatomical average vertical and horizontal position,recording the movements of the patients mandible, measuring therecording of the patients mandible, adjusting said lower cast laterallyand protrusively in accordance with said recording, mounting an uppercast in said articulator in proper position as determined by theposition of said lower cast, and mounting teeth in said casts, saidteeth properly occluding due to correct alignment of said upper andlower casts.

9. In a method of constructing artificial dentures comprising the stepsof mounting a lower cast of a patients mandible in an articulator,recording the movement of the patients mandible, measuring saidrecording, adjusting said lower cast laterally and protrusively inaccordance with said recording, mounting an upper cast in saidarticulator in proper position as determined by the position of saidlower east, moving said upper cast in the protrusive position, andadjusting articulating means to cause said articulator to reproduce saidrecording, and mounting teeth in said casts.

10. In a method of constructin" artificial dentures comprising formingan upper and lower east of a patients jaws, mounting said upper andlower casts in an articulator in centric relation, said last stepcomprising recording the movements of the patients mandible, adjustingsaid lower cast laterally and protrusiveiy in accordance with therecorded reading and mounting said upper cast in said articulator in aposition determined by said lower east, moving said upper east inprotrusive position and adjusting the condylar readings in saidarticulator to cause said recording to be reproduced by saidarticulator, and mounting teeth in said casts, said teeth properlyoccluding because of the correct alignment of said upper and lowercasts.

11. In an articulator, a base, vertical condylar posts mounted at therear of said base, said condylar posts ter minating in condylar heads,said condylar heads including rotatable elements having slots formedtherein, a maxillary bracket formed integral with a shaft, said shaftincluding means engaging said slots thereby pivotally securing saidmaxillary bracket in said articulator, an upper mounting plate securedto said maxillary bracket, said upper mounting plate having an uppercast secured thereto, a lower mounting plate secured to said base andadapted to receive a lower east, said lower mounting plate adjustablymoving said lower east laterally and protrusively and comprising amovable top plate, elongated screws secured to said top plate, a fixedbottom plate engaging said top plate, said bottom plate having wideslots formed therein receiving said elongated screws, ad-- justment nutsextending into said slots, said adjustment nuts having openings formedeccentrically therein, said openings receiving said screws, lock nutshaving threaded openings formed therein for receiving said screws, saidadjustment nuts adapted to move said top plate relative to said fixedbottom plate thereby adjusting the position of said top plate, said locknuts adapted to lock said top plate to said bottom plate in a fixedposition.

12. In an articulator, a base, vertical condylar posts mounted at therear of said base, said condylar posts terminating in condylar heads,said condylar heads including rotatable elements having slots formedtherein, a maxillary bracket mounted in said articulator formed integralwith a. shaft, the ends of said shaft extending into said slots therebypivotally securing said maxillary bracket in said articulator, an uppermounting plate secured to said maxillary bracket, said upper mountingplate adapted to have an upper cast secured thereto, a lower mountingplate secured to said base and adapted to have a lower cast securedthereto, said lower mounting plate being adjustable laterally andprotrusively and comprising a movable top member and a fixed bottommember, screw means secured to said movable top member, means engagingsaid screw means for adjusting said top member thereby adjusting theposition of said lower mounting plate.

13. in an articulator as set forth in claim 12, wherein said engagingmeans comprises a pair of adjustment nuts, each of said adjustment nutshaving an opening formed eccentricaliy therein, said eccentric openingscooperating with said screw means to move said top plate laterally.

14. In an adjustment plate for an articulator, a fixed bottom platehaving enlarged openings disposed at opposite sides ofthe plate thereof,a movable top plate engaging said bottom plate, said top plate havingelongated screws secured thereto and extending through said enlargedopenings in said bottom plate, adjustment nuts having a body portionwhich extends into an opening in said bottom plate, each of saidadjustment nuts having an opening formed eccentrically therein, each ofsaid eccentrically formed openings receiving an elongated screw therein,and lock nuts having threaded openings formed therein adapted to receivesaid screws, said movable plate being moved laterally upon rotation ofsaid adjustment nuts and said lock nuts being adapted to secure saidmovable top plate to said bottom plate when tightened on said screws.

15. In an adjustment plate for an articulator, a fixed bottom plate,said bottom plate having an opening formed therein, a movable top plateengaging said bottom plate, screw means secured to said top plate andextending through the opening in said bottom plate, adjustment meanshaving an opening formed eccentrically therein and receiving'said screwmeans, said adjustment means extending into the opening in said bottomplate, and lock means engaging said screw means, said adjustment meansadapted to move said topplate laterally with respect to said bottomplate and said lock mean adapted to lock said top plate securely to saidbottom plate.

16. In an adjustment plate for an articulator, a fixed bottom platehaving openings formed therein, a movable top plate having screw meanssecured thereto and extending through said openings in said bottomplate, means having-openings formed eccentrically therein, saidlastnamed openings engaging said screw means, said means being adaptedto move said top plate relative to said bottom plate, and means havingthreaded openings formed therein engaging said screw means for securingsaid top plate to said bottom plate in locked position.

17. In a method of constructing artificial dentures comprising the stepsof mounting a lower east in an articulator in the correct anatomicalaverage vertical and horizontal position, recording the mandibularmovements of the patient in the form of a Gothic arch, measuring theangle of said Gothic arch, adjusting said lower cast relative to thecenter of the hinge axis of said articulator in accordance with saidmeasurements, mounting an upper cast in said articulator to conform tothe position of said lower east, moving said upper cast in theprotrusive position and adjusting the condylar readings of saidarticulator so that the articulator will reproduce the Gothic archtraced by the patient, and mounting teeth in said casts, said teethbeing arranged to properly occlude due to the correct alignment ofsaidupper and lower casts.

13. In a method of constructing artificial dentures comprising the stepsof mounting a lower cast in an articulator in the correct anatomicalaverage vertical and horizontal position, recording the mandibularmovements of the patient in the form of a Gothic arch, measuring theangle of said Gothic arch, adjusting said lower cast so that thedistance from the apex of said Gothic arch to the midpoint of thehorizontal projection of the hinge axis of said articulator is inaccordance with the measurement of said angle, mounting an upper cast insaid articulator in accordance with the position of said lower east,adjusting the condylar reading of said articulator so that thearticulator will reproduce the Gothic arch traced by the patient, andmounting teeth in said casts, said teeth being arranged to properlyocclude because of the correct alignment of said upper and lower casts.

19. In a method of constructing artificial dentures comprising the stcpsof mounting a lower cast in an articulator in the correct anatomicalaverage vertical and horizontal position, recording the movements of thepatients lower jaw in the form of a Gothic arch, measuring the angle ofsaid Gothic arch, adjusting said lower east in said articulator so thatthe distance from the center of the horizontal projection-of the hingeaxis of said articulator to the apex of said arch conforms to themeasurement of said angle, mounting an upper cast in said articulator inaccordance with the position of said lower cast, adjusting the condylarreadings of said articulator so that the Gothic arch traced by thepatient will be reproduced by said articulator, and mounting teeth insaid casts, said teeth being arranged to properly occlude due to thecorrect alignment of said upper and lower casts.

20. In a method of constructing artificial dentures comprising mountinga lower east of the patients mandible in an articulator in the correctanatomical average vertical and horizontal position, recording thelateral and protrusive mandibular movements of the patient in the formof a Gothic arch by a Gothic arch tracing device,

locking together upper and lower elements of said Gothic arch tracingdevice utilizing a centric lock, thereby establishing centric relation,removing said centric lock from between said tracing elements, recordingthe protrusive relationship of the patients mouth by inserting a lockbetween said tracing elements after the patient has moved the mandiblein a protrusive position, measuring the angle formed by the Gothic archtracing, adjusting the position of said lower cast in accordance withthe reading of said angle, mounting an upper cast in said articulator ina position determined by the adjusted position of said lower east sothat the Gothic arch traced by the mandibular movements of the patientwill be reproduced when said upper cast is moved relative to said lowercast in said articulator.

21. In a method of constructing artificial dentures as set forth inclaim 20, rotating one or both of the articulator condylar posts to aproper position when an irregular Gothic arch tracing has been traced bya patient whose mandible has been shunted in a protrusive and lateralposition which varies considerably from normal, the proper position ofrotation of said condylar posts being determined when said articulatorduplicates the tracing traced by said patient, moving the upper cast ina protrusive position to seat in said protrusive lock, thereby causingsaid articulator to duplicate the patients condylar inclination, wherebyall mandibular movements of said patient will be reproduced when saidmaxillary cast is moved relative to said mandibular cast.

22. In an articulator, a base, vertical condylar posts mounted at therear of said base, said condylar posts terminating in condylar heads andbeing rotatable to compensate for variations in the protrusive andlateral position of the patients mandible, a maxillary bracket mountedin said articulator, an upper mounting plate secured to said maxillarybracket, an adjustable lower mounting plate secured to said base andadapted to laterally and protrusively adjust the position of a lowercast mounted thereon, said condylar heads including rotatable elementsmounted thereon, said elements being rotatable about an axis normal tothe axis of said posts to compensate for various condylar inclinationsof the patient, whereby rotation of said condylar posts and rotatableelements mounted on said posts enable a tracing by the patient to beduplicated on said articulator.

References Cited in the file of this patent UNITED STATES PATENTS1,799,528 Phillips Apr. 7, 1931 2,220,734 Shanahan Nov. 5, 19402,510,152 Stoll June 6, 1950 2,521,599 Neil Sept. 5, 1950

